Paul Scholes has said Louis van Gaal should not have reacted to Sam Allardyce's claim that Manchester United played long-ball football at West Ham, describing his news conference refuting the remarks as "bizarre."
Former United and England midfielder Scholes said United boss Van Gaal should have been big enough to ignore Allardyce's accusation, which came after the 1-1 draw on Sunday.
Speaking to the media ahead of United's Old Trafford clash with Burnley on Wednesday, Van Gaal produced a dossier of data which he insisted negated Allardyce's claims.
Statistics quoted in the four-page document suggested West Ham produced a higher percentage of long balls than United during the match.
However, speaking on BT Sport's Fletch & Sav show, Scholes said Van Gaal should have risen above the comments.
"Why would you react to a West Ham manager?" he asked. "It's different if it's a rival manager like Chelsea or Manchester City's, but at the end of the day you're the Manchester United manager.
"I found it all bizarre, to be honest with you, as I felt Allardyce's comments were light-hearted in the first place."
Scholes went on to question Van Gaal's use of club captain Wayne Rooney in midfield rather than as a striker, voicing his frustration at United's stop-start performances so far this season.
"It's not great to watch -- put it that way," he said. "I've heard Van Gaal say recently that United can't take risks, but what message does that send to the fans?
"It's all about taking risks as a Manchester United player. They're [the fans] used to watching United teams that play high intensity football and score plenty of goals, and that just hasn't happened this season.
"The two centre forwards -- whoever has been playing up there in different games -- have not been good enough either.
"He [Rooney] scores goals, creates them and gives endless amounts of energy. This is Wayne Rooney -- how many goals has he scored for Manchester United and England? He's wasted in midfield or on the wing. He's got to be playing up front."
Van Gaal has also come under fire from fellow countryman Pierre van Hooijdonk, who claimed "even the biggest clowns" are laughing at the 63-year-old.
The former Netherland striker said he could not believe the way things are going for Van Gaal at Old Trafford.
"I don't believe it when I look at Man United," former Netherland striker Van Hooijdonk told Voetbal International.
"After David Moyes they had to change, and LVG looked like a good solution. But apart from the results, the way they play is terrible. I don't recognize the hand of Louis van Gaal in anything.
"Even the biggest clowns are laughing about LVG. I know them, I played at [Nottingham] Forest. Men like Dave Bassett and Ron Atkinson. Now even Sam Allardyce questions LVG's capabilities."
Van Hooijdonk, who played under Van Gaal for the Netherlands, took aim at Radamel Falcao, claiming he would not normally have been a Van Gaal transfer target.
"It seems he didn't know what type of players United needed," Van Hooijdonk added.
"Take Falcao -- not a player that LVG often uses. I think the club wanted him, based on his statistics, but he was not LVG's choice. Because, especially with a striker, you must look at why and how he scores so many goals.
"What's the best system for him to play in? This is a bunch of good players without any cohesion."